The invention relates to an apparatus for pressing-in or pressure attaching belt connectors. Such machines are predominantly used in underground mines and have been known in numerous versions for decades.
For instance, German Patent (DE-PS) No. 1,042,988 shows a pressing-in device for wire hook type connectors. Wire hook type connectors are not sufficient any more for high tensile or high strength conveyor belts. Therefore, in such cases disc or plate type connectors are predominantly used. As a result, devices for pressing-in or pressure attaching conveyor belt connectors as shown, for example, by the Applicant's German Patent (DE-PS) No. 2,545,403 corresponding to part of the disclosure of U.S. Pat. No. 4,050,138 have been developed.
Due to new developments even these devices are not satisfactorily suitable any more for use, particularly in the manufacturing of conveyor belts, because the forces necessary for producing the belt connections could not be achieved by previous machines.
Because of the development of high tensile fibers, it is possible to manufacture very high strength conveyor belts, which require an application of a high force for pressing-in the conveyor belt connectors. With regard to the known types of connectors, which require on the one hand, higher pressing-in forces, and which on the other hand, cannot be sufficiently anchored or attached with the customary clipping, such currently known connectors as well as pressing-in machines exhibit particularly the following disadvantages.
The control of non-symmetrical closing movements by means of curves or cams is susceptible to wear and tear in underground operations in a coal mine, for example. The curves or cams are expensive to manufacture. They permit only limited pressing-in or pressure attachment forces, because the Hertzian compression on the curve limits the load capacity of cam controlled devices. Consequently, cam controlled pressing-in machines for the pressing-in or pressure attachment of heavy duty connectors in hard, high-strength belts, are no longer sufficient.
Furthermore, a close spacing arrangement of the crimp or staple shanks to be pressure attached, is required for these belts, to avoid an overly deep penetration of the connector elements into the conveyor belt. Such avoiding requires a clipping of the staple points. Because of the high pressure attachment forces, the conventional anchoring of the tips by clipping, which was customary up until now, is no longer sufficient. On the other hand, the cutting or clipping of the staple points cannot be avoided, since otherwise a larger number of connector sizes would have to be used for various belt thicknesses.